Electric light



Jan. 12 1926.v 1,569,216

C. W. DAKE ELECTRIC LIGHT Filed Feb. 23, 1923 /N VENTO/1 (Vania/S Waze.

l4 TTU/CNE Y To, all 'whom it may` Patented Jan. 12, 1926.

UNITED STATES camas w. nm, or cnrcaeo, ILLINOIS.

ELEQTRIG LIGHT. y l

concern.' Be it lmown that I, CHARLES `W. Daim, a citizen of the United States,residin at 'Chicago, in the county of Cook andv tate of Illinois, have invented a certain new and useful Improvement in Electric Lights, of which the following is a specification.

My invention relates to an improvement in electric lights for use especially in con- .i necton with locomotive electric head lights and similar purposes where an incandescent electric light is used as the source for an illuminating or search light ray associated with a parabolic reflector.

It is, of course, a known fact that the best place for such a source of light is at the focal center of the reflector, and that the farther away the sourcev gets from the focal center the less satisfactory becomes the light.

It is impossible to have all of the light at the focal center, `and I have discovered that the next best place is to have the'l light filament strung along the central axis of the reflector, passing through the focal point.

'1 Next to this the best place for the'light` is Vin a plane perpendicular to this axis and passing through the focal point.

Especially in connection with-locomotive electric headlights where the voltage is comparatively low, it is necessary, in or get a lamp which will comply with the necessary service conditions, to have a lament which is of comparatively great length,

and in the past it has been thepractice to provide the filament arranged in a grid in a plane perpendicular to the focal axis.

.I propose to provide in my bulb for incandescent light a comparatively large portion of the filament located on or immediately adjacent to and surrounding this focal axis and projecting both in front of and behind the focal point. I propose to locate the balance of thefilament in the plane perpendicular to this axis and passing through the focal point. Experience shows that this arrangement results in a maximum of illumination and prevents the presence of any dark spots or dark areas in the beam of light.

My invention is illustrated more or less diagrammatically in the accompanying drawings, wherein- Figure 1 is a perspective view of an elecder toi Application led February23f1923. Serial No. 620,561.-

tric light globe showing place;

Figure 2 is a detailed side elevation of the filament and the supporting anchorages;

the filament in Figure 3 is a. plan View of the bulb. v

Like parts are indicated by like characters.

A is the glass bulb or globe of the conventional' type of incandescent electric light. It is provided with a screw-threaded base A1 adapted to be screw-threaded into a socket and cemented as at A2. Projecting upwardly from the base is a support A3, of glass or other suitable material, in which are imbedded or inclosed conductors A4 and A. This support terminates at its upper end in a base AG from which project upwardly the three supporting arms A", A8, A, and a holding hook A1".

Passing through the wall of the base A* and associated with the conductor A4 is a conductor hook B, which is curved away from the filament and terminates on the focal line, where it supports the outward end of a coiled filament B1. This coiled filament extends inwardly along the focalline, passing through the focal point, and is held by the hook A1o at a point behind the focal plane. An inclined stretch or branch of this filament extends from the hook A10 to the support A", which terminates in the focal plane.` From here the filament extends to the hooks A8, A7, back to a point adjacent the hook A9, where it is The filament itself is preferably formed'.V

of a single closely coiled spiral wire of the usual type.y This coil is so fine andso close that for all practical purposes it may be treated and considered as a single straight wire, and while geometrically, ofcourse, the

size of the coiled wire portion is large in fact, nevertheless, being placed right on'the focal, line as 1t is, it may for all practical Elurposes be considered as an incandescent ament on the focal line.` The same comment applies to that part of the iilament lo-l siaged in a plane perpendicular to the focal of transverse filament sections located in a single lane intermediate the ends of and perpen 'cular to the longitudinal section and surrounding it, and a plurality of hooks upwardly and outwardly projectinor from said support, adapted to support said transverse sections.

2. In an electric light globe, a base, -a sup ort projecting upwardly therefrom wit section upwardly projecting from said base, a. holding hook adapted to hold the outer end of said longitudinal section, a plurality of transverse iilament sections located in a single (plane intermediate the ends of and perpen 'cular tothe longitudinal section and surroundin it, and a. plurality of hooks upwardly an outwardly projecting from said support, adapted to su port said v transverse sections, said rst mentioned holdsaid globe, a longitudinal filament ing hook being outwardly bowed to avoid said transverse filament sections2 and inwardly curved above them to a point in line with said support.`

3. In an electric light, a luminous lilament having a lon 't-udinal section lying substantially along t e axis of the lamp, and a plurality of transverse sections located in a single plane intermediate the ends of and perpendicular to the longitudinal section.

4. In an electric light a luminous filament having a longitudinal section lyin substantially along the axis of the lamp, an a plurality of transverse sections located in a single plane intermediate the ends of and perpendicular to the lon'itudinal section, and Substantially surrounding it.

5. In an electric light having a glass stem, a luminous filament upwardly projecting from said stein and lying substantiall along the axis of the lamp, a plurality o transverse sections located in a single plane intermediate the ends of and per endicular to the longitudinal section, an Supporting hooks upwardly and outwardly extending from said stem and adapted -to support and position said sections.

Signed at Chicago,`county of Cook, and State of Illinois, this 19th day of February, 1923.

CHARLES W. DARE. 

